The reduction of harmful pollutant emissions as well as CO 2 emissions emanating from motor vehicles will be of considerable interest in the coming decades. Emissions legislation will be the guiding principle in the development of new technologies and vehicles. More attention will have to be paid to off-road vehicles, especially tractors, if the production of healthy food and the maintenance of a cleaner environment are not to be compromised. Therefore, one the biggest challenges facing the automotive industry is to improve fuel economy, both to conserve natural resources and to limit pollutants and CO 2 emissions. Better fuel efficiency and consequently lower emissions will require new materials, new lubricants and low-emission fuel. Engine lubricants help to improve vehicle efficiency but contribute engine exhaust emissions. This paper deals with the influence of engine lubricants on diesel exhaust emissions. Investigations have shown a clear effect of lubricant oil on emissions, which depends on lube oil characteristics, especially sulfur content, metal content, volatility and density.

The primary energy consumption in the world has increased continuously. The most important primary energy source is oil. The supply of automotive fuels today is based almost entirely on oil, and the demand for liquid transportation fuels worldwide will rise significantly in the next fifty years. Growing energy consumption and decreasing fossil resources are reasons for increasing prices of fossil fuel. Besides limited availability, contribution to greenhouse effect and pollutant emission represent another problem of fossil fuel. Both of these problems can be overcome by increased application of renewable biofuels. Therefore, great effort is made to supplement the primary energy sources by including renewable energies. There are alternative fuels 1st and 2nd generation. Some of them show high potential for reduction of engine out emission. But there are economical and technical barriers when such fuels are applied. This paper shows both advantage and disadvantage of alternative fuels, especially when used for diesel engines.

Abstract

U teku}oj dekadi ovog milenijuma proizvo|a~i motora moraju posti}i dvostruko smanjenje potro{nje goriva, pa time i emisije CO 2 i desetostruko smanjenje nivoa emisija, pre svega NO x i ~estica. Za dostizanje tog cilja moraju se razviti nove specifikacije ulja, ~iji doprinos smanjenju potro{nje goriva i nivou {tetnih emisija postaje sve va`niji. Trend razvoja ulja kre}e se u pravcu ni`ih viskoznih gradacija sa ni`im sadr`ajem sumpora, fosfora, sulfatnog pepela i ni`om isparljivo{}u, ~ime se posti`e smanjenje emisije, kao i potro{nje goriva. Klju~ne re~i: motori SUS, motorna ulja, emisije.